//
// Created by Selim Mustafaev on 24.09.2023.
//

#ifndef NES_OAM_H
#define NES_OAM_H

#include "Shifter.h"
#include <cstdint>
#include <cstddef>
#include <tuple>

namespace nes {

    class Ppu;

    struct SpriteInfo {
        uint8_t y = 0xFF;
        uint8_t id = 0x00;
        uint8_t attr = 0x00;
        uint8_t x = 0xFF;
    };

    struct SpritePixelInfo {
        uint8_t pattern = 0;
        uint8_t palette = 0;
        uint8_t priority = 0;
    };

    class Oam {
    public:
        static constexpr size_t OAM_SIZE = 64;
        static constexpr size_t MAX_SPRITES_PER_SCANLINE = 8;
        static constexpr uint8_t SPRITE_PALETTE_OFFSET = 4;

    public:
        explicit Oam(Ppu* ppu);
        void setAddress(uint8_t address);
        [[nodiscard]] uint8_t read() const;
        void write(uint8_t value);
        void dmaTick(uint64_t cycles);
        void dmaStart(uint8_t page);
        bool dmaActive() const;
        uint8_t address() const;

    public:
        bool detectVisibleSprites(int16_t scanline, bool bigSprite);
        void loadShifters(int16_t scanline, bool bigSprite, bool patternSprite);
        void updateShifters();
        [[nodiscard]] SpritePixelInfo getPixel();
        [[nodiscard]] bool spriteZeroBeingRendered() const;

    private:
        [[nodiscard]] uint8_t flipByte(uint8_t byte) const;

    private:
        Ppu* _ppu;
        uint8_t _address = 0x00;
        SpriteInfo _data[OAM_SIZE];
        SpriteInfo _visibleSprites[MAX_SPRITES_PER_SCANLINE];
        Shifter _spriteShifters[MAX_SPRITES_PER_SCANLINE];
        uint8_t _visibleSpriteCount = 0;
        bool _spriteZeroVisible = false;
        bool _firstVisibleSpriteBeingRendered = false;

    private:
        uint8_t _dmaPage = 0;
        uint8_t _dmaAddress = 0;
        uint8_t _dmaData = 0;
        bool _dmaActive = false;
        bool _dmaDummy = true;
    };

}

#endif //NES_OAM_H